Cam operated clutch



May 9, 1950 FAST 2,506,713

CAM OPERATED CLUTCH Filed Nov. 9, 1945 3 Sheets-Sheet 1 IN V EN TOR.

y 50 M. L. FAST 2,506,713

CAM OPERATED CLUTCH Filed Nov. 9, 1945 3 Sheets-Sheet 2 27 INVENTOR.

May 9, 1950 FAST 2,506,713

CAM OPERATED CLUTCH Filed Nov. 9, 1945 5 Sheets-Sheet 5 l F r N i l 5 I t 1N1 "EN TOR.

Patented May 9, 1950 CAM OPERATED CLUTCH Marion It. Fast, South Benet, Ind., assignor to Dodge Manufacturing Corporation, Mishawaka, Ind., a corporation of Indiana Application November 9, 1945, Serial No.- 627,676

3- Claims. I

My invention aims to provide an improved friction clutch of the type in which clutching pressure is applied by forcibly contracting an annular series of balls acting. wedgingly between an abutment and an axially movable thrust-transmitting: member, the thrust exerted on said member being: transmitted to the presser plate of the friction clutching means.

A clutch of one practicable construction embo'dying the invention is shown for illustration in the accompanying drawings wherein":

Fig. 1' is a View half in: longitudinal section and half irr side elevation of the illustrative clutch shown in closed or applied condition.

Fig;- 2' is a portion of a longitudinal section showing the position of the balls when the clutchis' released.

Fig. 3 is a partial cross section taken on the line 3-3 of Fig. 1:, looking in the direction of the arrows.

Figz i s a partial cross section on the line l d of Fig; 2;.

Fig. 51s an end: elevation, partly broken" away, of a ball spacing ring incorporated the illus trati ve clutch.

Fig. 6 is a longitudinal section of said ring.

Figs. and 8' are similar sections of ball spacing'rings made assheet metal stam-ping's, that of Fig; 8 being" shown in association with certainotlier elements.

Figs 9- and i are anenlarged elevation and cross section of the joint in an expansibl'e spring" ringincorporated in the illustrative clutch.

1'1 15* an enlarge-el View in longitudinal sec-- ti'on ofia' portion of the pressure apply-i'ngmechanism in: released condition, and indicating indotted lines the positions of the parts when the clutch is applied.

Fig-i 1'2 isa rear end elevation of the clutch on-a' reduced scale; partly crosssection on the line- |2'- I 2 'ofFig 1'. I

Thedrawin'gs represent anembodiment-of the invention in a large friction disc clutch comprising plates I and zicoacti've for clamping the disc 4, said pllatesbeing carried by and indrivingconnectionw-itliahub-or sleeve-3 tobe fixed on a' drivingor drivenshaftand said disc 4 beingheld-b-y a ring Et'o be fi xed to-the-rotatablemember (not shown) towhich the shaft is to be clutched. Theplate I which rnaybe axially fixed or" otherwise held from outward displacement, sustains thepressure applied by the axially. movable presser plate 2, the latter being. slidable on and; suitably splined to. the hub-.- In the specific construction shown; desirable for a large friction disc clutch, the hub 5 is integral with the plate I and has the press'er plate 2 splined thereto by means of gear-like teeth on' the l'iub-slidably' in'terfitted with internal teeth ef'the presser plate. The" friction disc is shown similarly splined' to; its carr ing ring a by peripheral disc teeth 7- slidably i-nte'rfi-tted with internal teeth of saidring. A plurality of clutch-releasing springs 87 compressed between and reacting against the plates I and 2' force the press'er plate 2 rear wardl y. normally holding it as far away from the plate I as it is permitted to go.

The pressure applying mechanism of the illu's trative' clutch comprises a contracti'ble annular series of steel balls 9 acting wedgingl'y between' a pair of hardened metal rings Hi and II having outwardly di'i/"erging adjacent end faces engaged" by the balls; these rings being slidably fitted on the hub. the ring Ill being axially movable and abutting an axially movable exteriorly screwthread'ed thrust transmitting member [2 carrying an adjusting ring or nut f3" screwed thereon and' abutting the p-resser plate 2. and the ring I I functioning as anaXially fixed reaction memher or thrust-sustaining abutment, being held in place in this instance by a snap ring I4',. i. e. a contractible split ring engaging an annular groove in the hub. The ring Ill could be integral with the member I2 but for simplicity and economical manufacturing practice is made as a separate hardened metal element, and for a similar reason the thrust-sustaining abutment II is provided by a separate hardened metal ring held against displacement rearwardly by a snap ring. The rings It and II instead of being hardened could be faced" by hard metal liners or washers.

The" thrust-transmitting member I2, which is cup-shaped'and' contains the balls and ring I'Il in the tubular part [5 thereof, is slidably'fitted' ori the hub but rotates in unison with the clutch" plates, being held in driving. connection withtand in fixed angular relation to the" presser plate, by" dbwel pins I 6' fixed in said plate and fitting slidably in said member- There is no need to spline" the rings Ill' and H to the hub.

It will be understood that as the balls 9 are forced inwardly, the thrust exerted on the" ring lll is transmitted by the member I2 and adjustin ring or nut l't there'on to the presser plate 2ft)!" forcing it into disc-clamping coaction with the reaction plate I or in other words for applyingor closing the clutch, and that in the! release action ofthe clutch the'pres'sure of the clutch-releasing springs 8; transmitted by the presser plate and elements I 3; I2" and I'ILw-ill force-the balls'-out-' wardly, their outward movement being limited in this instance by the tubular part 15 against which they bear when the clutch is open or fully released. In will also be understood that by axially adjusting the ring nut 13 the axial relation of the presser plate 2 to the plate I in the released condition of the clutch is affected, whereby the clutch can be adjusted to permit precisely the right axial movement as a unit of the abutting elements 2, 13, I2 and I0, and the clearance between the friction clutching elements may be taken up to compensate for wear.

The clutch is applied and released by reversely shifting an axially movable cam sleeve ll fitting slidably in i5 and having a neck portion l8 slidably fitted on the clutch hub. In the release position of the cam sleeve indicated in Fig. 2, the outwardly pressed balls are in contact with l5 and with outer portions of the confronting faces of the rings l0 and H. Upon forcing the cam sleeve forwardly from its release position, its interior cam surface coacts with the balls to force them inwardly, thereby forcing the ring ID in a direction away from the ring II. The cam surface is shaped to effect contraction of the annular series of balls to the position shown in Figs. 1 and 3 by forward movement of the cam sleeve from its releasing position to the Fig. 1 position. Forward movement of the cam sleeve is limited by engagement with the balls of a stop shoulder l9 in the cam sleeve. The interior cam surface of the sleeve is preferably so shaped that when the balls are seated against said shoulder l9 they bear outwardly against a part of said surface which is either cylindrical or of very slightly larger diameter than the so-called highest point of the cam or part thereof immediately in front of the plane the ball centers. In other words, the cam surface is shaped to effect a self-locking of the clutch in applied or closed condition. Retractive fovement of the cam sleeve is limited by a back stop provided in this instance by a snap ring 20. There is no need to spline the cam sleeve to the hub, and preferably it is freely rotatable as well as slidable thereon. For actuating the cam sleeve, it may be connected in a conventional or any suitable manner to actuating means. As shown, it has swiveled thereto a collar 2 I fitted in the annular groove in 18, said collar comprising mating half parts separably connected by the bolts 22 and having diametrically opposite trunnions 23 for engagement by the yoke arms of a clutch-throw lever (not shown).

Among other advantages of the construction described is the cooperation of the cam sleeve l1 and cup-shaped thrust-transmitting member l2 with each other and with the hub to completely enclose the annular series of balls and the rings ID and I I, preventing entrance of dirt or foreign matter to the ball groove formed by and between said rings. Also the cup-shaped member 52 having the cam sleeve slidable therein obviates the need of an extension of the cam sleeve to hold the balls in their released or outer positions, thus shortening the mechanism and contributing to compactness of construction.

To allow a sufilcient axial movement of the presser plate 2 for proper clutch release, and yet to obtain a tight closing of the clutch by a short radial movement of the balls and with mechanical advantage, the rings Ill and l i have their confronting faces formed with outer ball-engaging portions diverging at a greater angle than the angle of divergence of inner ball-engaging portions of said faces. In the illustrative mecha nism the ring H) has outer conical and inner flat ball-engaging surfaces It! and I0 confronting the conical ball-engaging face H of the ring H, the included angle between 53 and i i being accordingly larger than the included angle between la and I l l'he balls during a substantial part of their inward movement are in contact with Hi but are forced between H3 and i l as the annular eries is further contracted. In applying the clutch, as the balls are forced inwardly in contact with w and H a relatively large proportion of axial movement is imparted to the presser plate 2, after which the friction clutching elements are pressed tightly together or against one another by the further forcing of the balls inwardly in contact with the fiat surface NJ", the latter action being accomplished with mechanical advantage since the pressure applied to contract the annular series of balls is parallel with the surface lll and at only a relatively small angle (e. g. 22 to the beveled surface H. In this connection, the interior cam surface of the cam sleeve I! is shown shaped to effect first a quick inward movement of the balls in contact with the surface 56*- and then a more gradual inward movement. In the releasing action as soon as the balls move outwardly from contact with the flat surface la the clutch may open fully as fast as the cam sleeve H is retracted. According to the particular design of the illustrative mechanism, the slant of the surface I0 to the vertical is twenty degrees and the slant of the surface I l is twenty-two and one-half degrees, so that the included angle between it and Il is forty-two and one-half degrees; it being understood that this is exemplary and that the design of the mechanism with respect to the proportions and arrangement of the balls and ring surfaces with which they contact and the angle or angles of divergence of such surfaces may be variously modified to suit different requirements and conditions.

Provision is made for maintaining the balls 9 in separated relation and guiding their movements as the annular series expands and contracts, whereby to avoid the increased resistance to actuation that would result from congregating of balls in their outer positions in contact with one another and consequent crowding and shoving of balls laterally by one another as they are forced inwardly in contact under pressure with the elements which they wedge apart. To relieve the mechanism from such increased resistance is especially important in applications thereof to clutches of large size or for large torque transmission, in which the applied pressures are such that crowding and pushing of the balls against one another as they are forced inwardly would objectionably augment the effort required for actuation.

Fitted on the clutch hub between the rings 9 and I0 is a spider-shaped ring 24 whose radiating arms 25 extend between and space the balls from one another and guide them for movement inwardly and outwardly, the form and proportions of the spacer ring being appropriate for accommodating the balls in their inner position and for spacing them in their outer positions, though in both inner and outer positions the balls must of course protrude from the spacer ring beyond the tips of said arms as well as beyond the opposite faces of the ring. As shown, the arms 25 extend outwardly beyond the circle of centers of the balls in their inner positions such a distance that the balls in their outer positions are sufiiciently within the ring to be held in spaced or separated relation. Reconciliation of the duty of pa n the balls in their outer positions with the necessity of clearance between the spacer ring and part l for the cam sleeve H requires that the axial movement imparted. to the presser plate 2 by contracting the annular series of balls be accomplished with a movement of the balls through a. radial distance not much if any greater than half of the diameter of the; balls. This distance in the illustrative mechanism is substantially less than half of the diameter of the balls, which is particularly favorable for utilization of. the kind of spacer ring described. Other conditions necessary to be fulfilled by the mechanism incorporating the spacer ring. are a sufficient clearance between the clutch hub and. balls in their inner positions to accommodate the central portion of the ring encircled. by the annular series. of balls, and a suificient clearance between the inner portions of the rings iii and ii in the released condition of the mechanism toaccommodate the spacer ring without obstructing release movement. of the ring it The spacer ring 2%, though susceptible of being out in the: form shown. from a metal plate, may be. more economically made. as: a die casting; In the form shown, the. ring is characterized. by closely spaced rmialv gnide ways having. semicircular inner portions andby arms 25 having gradually increasingly widened base portions formed between. the arcuate walls of adjacent guide-ways (Fig. 5;) This gives a ring. or strong and rugged construction, capable of withstanding; the; strains imposed. by action of the balls against the radiating arms; andv it permits utilie zation of a; nnritiplicity of balls in closely spaced; relation, as is desirable for effective distribution of the pressure imposed on and transmitted by the annular series of balls. The side walls of the ball-guiding ways beyond their semicircular inner portions are tangent to the arcs 26 and par allel either to radii bisecting said arms or to radii bisecting' the guide-ways for the balls. In the latter case, the side walls orevery individual guide-way would be parallel with each other, which may be preferable in some cases: though the guide-ways of the spacer ring shown are slightly flaring, since the: opposite sides of the portions. of the arms 7.5 extending beyond the circle oi centersot the arcs 25 are shown tangent to said arcs. and parallel to radii bisecting said arms, as indicated in Fig. 5 by the surfaces 2% and 25 cilitate manufacture of the: spacer ring as a die casting.

There is no need to spline the spacer ring to the clutch hub; Preferably it is freely rotatable thereon; to permit rota-ti've movement relativeto the hub of' the spacer ring and annular series of balls in case such relative movement would want to occur in any phase of actuation or release 01 while the clutch rotates in released condition. Nor is there any need to restrain the spacer ring from axial movement, though it could be held adjacent to I i by appropriate means, as by a spring (not shown) compressible between to and 24 or by a small snap ring (not shown) adjacent to 2d.

The clearance shown between Ii! and 24 is sufiicient to accommodate a spacer ring of such width or longitudinal thickness that in all relative positions of the ring and balls the plane of the ball centers would be in the spacer ring or between the planes of its opposite end faces. However it is unnecessary to use such a wide spacer ring. With the thinner spacer ring 24 in the illustrative mechanism the plane of centers of the balls when in their outer positions is in the spacer ring,

pointer design is provided to'f'aell) though as the balls approach their inner positions their centers pass out from the spacer ring, this having been found to be permissible.

There is shown between It and 2d a contracted spring ring 21 operating expansively and pressing outwardly against the balls, said spring ring being held against it by the balls. This spring ring 2? may consist of a piece of resilient wirebent into ring form and having overlapping end portions of reduced thickness as indicated at 21 and 21 in" Figs. 9 and 10. Although in the illustrative mechanism the clutch-releasing springs 8 may be depended upon. to force the balls outwardly when the cam sleeve I7 is retracted, the spring ring 2'! may be employed to assist such acti'on or to promote quick release of the balls, and in other constructions such a spring ring may be utilized either to supplement the action of clutchreleasing springs or as the means for the function of forcing out the balls, which function is of course assisted by the centrifugal force on the balls.

Fig. 7 shows in section a spacer ring 28 similar to 2 except that therirrg 28 is made as a doublewal'led sheet-metal stamping having the fold in. the metal atv its center as indicated at 2 9 As shown in Fig. 8, a similar wider ring 38' could be used instead: oi 2t. with. the spring ring 2? arranged within the spacer ring to.

It will be observed that the described mechanism, in addition to having the advantageous. features and characteristics hereinbefore indicated, is of a construction. which is. quite simple and easy to: assemble; that the hub sleeve extension behind the presser plate is or may be of uniform outside diameter, except for annular grooves therein for the snap rings i l and said hub extension being devoid of any flange or external shoulder or projection, thus permitting: the; several annular elements fitted thereon to be of the" same bore and: to be easily successively applied by slipping them over the rear end of said hub extension; that there are no interengaging keys and keyw'ays between said elements and the hub (though the member i2 isheld in driving connection with-the pres'ser' plate by the dowel pins i=5) and that-the balls can be assembled in the mechanism without special difliculty or liability of spilling outas they are inserted. In assembling, the hub having the friction clutching means and the elements i2, iii in assembly'th'erewith can be held vertical position and the balls can be dropped into place, the spring ring 2'2 having been first-introdueedinto-the cup-like member t2 and being held contracted whiledropping inthe The spacer ring 2? maybe applied before ballsa or after dropping in the balls. The ring i i andits retaining snap ring M may then by applied, whereupon the cam sleeve or actuator I? can be applied and retained in its proper limits of travel by the snap ring 20.

As shown in Fig. 12, the adjusting nut is of the illustrative clutch comprises an interiorly screwthreaded split ring contractible against the threads of the member It for securing the ring in its adjusted position relative to said member; the end portions of said ring at opposite sides of its split or gap 3! being connected by a cap screw 32 to be tightened for contracting the ring; the cap screw being parallel to a tangent and entirely within the ring. As shown, the screw head 33 bears against a spring washer 34 seated at the inner end of the bore 35 in which the screw head fits, said screw head being cylindrical and having a socket for engagement by a wrench. The ring I3 is provided with angularly spaced barring holes, one being shown as 36, engageable by a bar or rod to be used as a lever for rotating the adjusting nut when the screw 32 is loosened sufficiently to permit such operation.

It will be understood that the invention or features thereof may be variously applied to large and small clutches, including multiple disc clutches, having friction clutching means including an axially movable presser plate to which pressure is applied for pressing the friction clutching elements together or against one another.

The clutch herein described embodies an invention described and claimed in my co-pending application Serial No, 520,469, filed January 31, 1944, now issued as Patent 2,397,414, dated March 26, 1946, which invention is also shown but not claimed in my co-pending application Serial No. 520,470, now Patent No. 2,443,901, issued June 22, 1948, for Locking means for clutch adjusting rings.

I claim:

1. A friction clutch having pressure applying means comprising a contractible annular series of balls and confronting annular members having outwardly diverging faces contacting with the balls at opposite sides of the plane of ball centers, one of said members being axially movable and normally coacting with the other to maintain said series in an expanded condition and being forcibly displaceable in a direction away from said other by the wedging of the balls therebetween as said series is contracted, and a radially expansible spring ring consisting of a resilient wire of round cross-section bent into ring form and having overlapping reduced end portions arranged within the annular series of balls to one side of the plane of ball centers and held by the balls against the adjacent one of said members, said spring ring being sprun into the annular crotch between said series and adjacent one of said members and normally resiliently urging the balls outwardly.

2. A friction clutch having pressure applying means comprising a contractible annular series of balls and confronting annular members having outwardly diverging faces contacting with the balls at opposite sides of the plane of ball centers, one of said members being axially movable and normally coacting with the other to maintain said series in an expanded condition and being forcibly displaceable in a direction away from said other by the wedging of the balls therebetween as said series is contracted, a radially expansible spring ring consisting of a resilient wire of round cross-section bent into ring form and having overlapping reduced end portions arranged within the annular series of balls to one side of the plane of ball centers and held by the balls against the adjacent one of said members, said spring ring being sprun into the annular crotch between said series and adjacent one of said members and normally resiliently urging the balls outwardly, and a flat ball-spacing ring of a thickness less than half of the diameter of the balls arranged between said spring ring and the other of said members.

3. A friction clutch having pressure applying means comprising a contractible annular series of balls and confronting annular members having outwardly diverging faces contacting with the balls at opposite sides of the plane of ball centers, one of said faces comprising an annular fiat surface and the other comprising a conical surface confronting said fiat surface, one of said members being axially movable and normally c0- acting with the other to maintain said series of balls in an expanded condition and being forcibly displaceable axially in a direction away from said other by the wedging of the balls therebetween as said series is contracted, and a radially expansible spring ring consisting of a resilient wire of round cross-section bent into ring form and having overlapping reduced end portions arranged Within the annular series of balls at the side of the plane of ball centers adjacent to said flat surface and held by the balls against said flat surface, said spring ring being sprung into the annular crotch between said flat surface and series of balls and normally resiliently urging the balls outwardly and against said conical surface.

MARION L. FAST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,913,030 Hux June 6, 1933 2,010,925 Nahashian Aug. 13, 1935 2,185,714 Scherer Jan. 2, 1940 2,367,390 Firth et a1 Jan. 16, 1945 2,376,799 Miller May 22, 1945 2,397,414 Fast Mar. 26, 1946 2,401,864 Gerst June 11, 1946 2,402,897 Kindig et al June 25, 1946 2,407,060 Croft Sept. 3, 1946 FOREIGN PATENTS Number Country Date 209,456 Great Britain Jan. 11, 1924 379,921 Great Britain Sept. 8, 1932 455,222 Great Britain Oct. 12, 1936 

